RESUMO
In the title hybrid salt, (C7H11N2)3[Cr(C2O4)3]·4H2O, the central Cr(III) ion of the complex anion (point group symmetry 2) is coordinated by six O atoms from three chelating oxalate(2-) ligands in a slightly distorted octa-hedral coordination sphere. The Cr-O bond lengths vary from 1.9577â (11) to 1.9804â (11)â Å, while the chelate O-Cr-O angles range from 82.11â (6) to 93.41â (5)°. The 4-(di-methyl-amino)-pyridinium cations (one situated in a general position and one on a twofold rotation axis) are protonated at the pyridine N atoms. In the crystal, N-Hâ¯O and O-Hâ¯O hydrogen bonds link the cations and anions into a three-dimensional network. π-π inter-actions between the pyridine rings of adjacent cations provide additional stabilization of the crystal packing, with the closest centroid-to-centroid distances being 3.541â (1) and 3.575â (1)â Å.
RESUMO
The Fe(III) ions in the hybrid title salt, (C7H11N2)[Fe(C2O4)2(H2O)2]·0.5H2O, show a distorted octa-hedral coordination environment, with four O atoms from two chelating oxalate dianions and two O atoms from two cis aqua ligands. The average Fe-O(oxalate) bond length [2.00â (2)â Å] is shorter than the average Fe-O(water) bond length [2.027â (19)â Å]. The ionic components are connected via inter-molecular N-Hâ¯O and O-Hâ¯O hydrogen bonds into a three-dimensional network.